Notification入门

        题外话：在Android中服务必须在Actvity创建后，方可获得，否则会出现错误：java.lang.IllegalStateException: System services not available to Activities before onCreate()。

        主要功能：实现在Activity中发出通知、删除通知、在通知中启动Activity

        主Activity代码：

import android.app.Activity;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class SimpleNotificationActivity extends Activity {
	private final String notifictionService = Context.NOTIFICATION_SERVICE;
	private final int icon = R.drawable.icon;
	private static int createdNums = 0;
	private final String tickerText = "通知内容：该起床了！";

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		Button startNotificationButton = (Button) findViewById(R.id.startNotificationButton);
		startNotificationButton.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View v) {
				NotificationManager notificationManager = (NotificationManager) getSystemService(notifictionService);
				long when = System.currentTimeMillis();
				Notification notification = new Notification(icon, tickerText, when);
				String contentTitle = "学校通知";
				String contentText = "6：30分必须起床，否则罚跑操场10圈！！！！！！！！";
				//Intent notificationIntent = new Intent(SimpleNotificationActivity.this, SimpleNotificationActivity.class);
				 Intent notificationIntent= new
				 Intent(SimpleNotificationActivity.this,AnotherActivity.class);
				// PendingIntent contentIntent =
				// PendingIntent.getActivity(getApplicationContext(), 0, null,
				// Intent.FLAG_ACTIVITY_NEW_TASK);//不在通知栏启动Activity
				PendingIntent contentIntent = PendingIntent.getActivity(getApplicationContext(), 0, notificationIntent, Intent.FLAG_ACTIVITY_NEW_TASK);// 在通知栏启动Activity,并打开新的Task栈
				notification.setLatestEventInfo(SimpleNotificationActivity.this, contentTitle, contentText, contentIntent);
				notification.defaults |= Notification.DEFAULT_LIGHTS;
				notificationManager.notify(3, notification);

			}
		});
		Button removeNotificationButton = (Button) findViewById(R.id.removeNotificationButton);
		removeNotificationButton.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View v) {
				NotificationManager notificationManager = (NotificationManager) getSystemService(notifictionService);
				notificationManager.cancel(3);
			}
		});

		setTitle("我是第" + createdNums++ + "个对象！！！！！");// 验证由自身跳转回自身的情况：创建新对象
	}

	@Override
	protected void onRestoreInstanceState(Bundle savedInstanceState) {
		System.out.println("恢复活动状态——如果没有我，用户数据无法恢复，而用户也会出离愤怒");
		super.onRestoreInstanceState(savedInstanceState);
	}

	@Override
	protected void onSaveInstanceState(Bundle outState) {
		System.out.println("保存活动状态——如果我不保存用户数据，你想恢复也恢复不了");
		super.onSaveInstanceState(outState);
	}

	@Override
	public boolean onKeyUp(int keyCode, KeyEvent event) {
		//在模拟器下，大写字母按键的录入捕获的是两个键值（字母键+功能键）
		System.out.println("用户按下的键是————————————————————————————————————————————————"+keyCode + "、" + event.getDisplayLabel() + "、" + event.getCharacters());
		
		return super.onKeyUp(keyCode, event);
	}

}

 辅助Activity代码

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class AnotherActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		TextView textView=new TextView(this);
		textView.setText("我是由Notification跳转过来的");
		setContentView(textView);
	}

}

 布局代码

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">
	<TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/hello" />
	<HorizontalScrollView android:id="@+id/horizontalScrollView1" android:layout_width="wrap_content" android:layout_height="wrap_content">
		<LinearLayout android:id="@+id/linearLayout1" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="horizontal">
			<Button android:text="添加通知" android:id="@+id/startNotificationButton" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>
			<Button android:text="删除通知" android:id="@+id/removeNotificationButton" android:layout_width="wrap_content" android:layout_height="wrap_content"></Button>
		</LinearLayout>
	</HorizontalScrollView>
</LinearLayout>